×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

2000KVA Transformer secondary taps

2000KVA Transformer secondary taps

2000KVA Transformer secondary taps

(OP)
Hello,
I am confused about the rules for secondary feeder taps on a transformer.
Basically, I have a 4160/480, Delta/Wye, 2000KVA transformer. I would like to feed 2x480VAC MCC line ups (1x1600amp bus and 1x1200 amp bus).
I was planning on placing the transformer directly outside an existing building adjacent to the MCC line ups (the MCCs are within the building). This however may be changing for other reasons.

My question is:
If I plan to connect the feeds for both MCCs "inside" the transformer secondary enclosure itself and run the two separate feeds directly to the MCCs in there own conduits, are these still considered "taps". If not, are there length limits or cable size issues that I need to consider?

I suspect that the new transformer location may be outside of the 25ft length limit specified in NEC240.21. Other than putting a low voltage switchgear line up in between the transformer and the MCCs (1 feed from the transformer to the LV switchgear with 2 sub feeds to the LV MCCs) what other options do I have?

Thanks
Robert  

RE: 2000KVA Transformer secondary taps

240.21 (C) covers transformer secondaries.  Outside secondary conductors are treated differently.   

RE: 2000KVA Transformer secondary taps

(OP)
Thanks for the response but, how are they treated differently? Do I not have the same length constraint?
Are there other references that you know of that I can review for the rules concerning secondarys that originate for outside locations?
 Could anyone tell me where I can find this type of information?

RE: 2000KVA Transformer secondary taps

Read the code.

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources